Device for amplifying or generating electric oscillations of very high frequency



March 13, 1951 DEVICE FOR AMPLIFYING OR GENERATING ELECTRIC (5 DE VRIES2,545,073

OSCILLATIONS 0F VERY HIGH FREQUENCY Filed Feb. 12, 1947 got: VRIESINVENTOR A GEN T charge tube having a wall Patented Mar. 13, 1951 PATENTo FF1cE fj- DEVICE FOR AMPLIFYING OR GENERATING ELECTRIC OSCILLATIONS FVERY HIGH FREQUENCY Gerrit de Vries, Eindhoven, Netherlands, assignor toHartford National Bank and Trust Company, Hartford, Conn., as trustee QApplication February 12, 1947, Serial No. 728,044 e In the NetherlandsJune 14, 1944 This invention relates to a device for generating oramplifying electric oscillations of very high frequency; this devicecomprises an electric dismade at least in part of insulating material,the flow of electrons passing through the tubewith variable intensityand inducing high-frequency currents in a circuit arranged outside thetube and comprising a slit. 'The'term',circuit"suggests either twoconduc- "t'or's" separated fromeach other by a slit and connected by animpedance or a cavity resonator which in a simple form is constituted bya solid of revolution formed by a single circular conductor, a slitbeing left between the ends of the conductor.

In such a device the flow of electrons is controlled in such manner thatthe number of electrons passing through a given tube section varies withthe frequency. If such a pulsating flow of electrons is conducted alonga slit in a circuit of the form as described before, high frequencycurrents are set up in this circuit. It has now been found that at theareas where conductive parts of the said circuit are adjacent the tubewall discharge phenomena may occur between these parts and the wall madeof glass, quartz or like material. It is not impossible that the sprayand ionization phenomena occurring in the case of very high frequenciesinvolve losses which cause undesirable heating apt to lead to damage ofthe device.

This difliculty can be avoided entirely by the use of a device foramplifying or generating electric oscillations of very high frequency,said device being provided with an electric discharge tube having a Wallmade at least in part of insulating material, on the outside of which isarranged a circuit having a slit and an insulating part of the wall ofthe tube opposite to the adjacent conducting parts of this circuit,being 10- cally provided with conductive coatings each of which isconductively connected to a part of the said circuit.

The term local coating is to be understood to mean a layer which is somounted on the tube wall that this layer and the tube wall are no longerseparated by an air layer, the said coating being only, applied to thoseparts of the tube wall which face the said conductors of the circuit.

It has now been found that the use of this means avoids any trouble fromdischarge phenomena liable to cause damage to parts of the device.

The conductive coating may be made of differin materials and applied invarious ways,

I section 1,'rubuc Law 690, August 8, 194a 1 .iil'latent expires June14, 1964 i V ,1; 2'Claims. (Cl.3155) thus, for example, the tube may becoated with small plates of metals, such as nickel, copper or the like;alternatively, the coatings may be arranged in the shap of rings tosurround the tube. The application of the coatings may be effected in asimple manner by applying a metal compound to the wall, dissociating itby heat and burning-in the meta] precipitate thus formed. A metal which.is especially suitable to be applied in thismanner-is platinum, it beingpossible to start with a readily dissociated platinum compound, forexample platinum chloride dissolved in nitrocellulose or platinumresinates which are applied in the form of any suspension anddissociated by heat, the platinum precipitate being then burnt-in.

The invention may be used with devices for generating or amplifyingelectric oscillations of very high frequency, a circuit which, asalready set out hereinbefore, may have widely difiering shapes, butwhich at any rate must have a slit in the proximity of the tube wall,bein arranged on the outside of the tube. A very simple form ofconstruction is that in which the tube is surrounded by a so-calledcavity resonator, that is to say a solid of revolution which is formedby a single circular conductor which comprises a slit; on either side ofthe slit the conductor may have a flange which is just opposite the tubewall, these flanges being connected, according to the invention, toconductive coatings of the tube wall.

According to a particular form of construction of the device accordingto the present invention the connection of the conductive Wall coatingsto the parts of the circuit is established by means of flexible elementswhich may be formed, for example, by arcuate or corrugated rings, aplurality of bent strips or the like.

In order that the invention may be clearly understood and readilycarried into effect, it will now be set out more fully with reference tothe accompanying drawing which illustrates part of the device accordingto the invention.

Referring to the single figure of the drawing, I designates a part ofthe wall of an electric discharge tube, said part being made ofinsulating material. The wall I is surrounded by two conducting parts 2separated by a slit 3 and united to form a circular conductor 4 whichconstitutes a cavity resonator. A heater [0 for a cathode source ofelectron emission H, is provided at one extremity of the tube wall I,and the electron beam is formed by the focusing electrode l2 and theaccelerating electrode l3 and passes along the insulating wall portionof th tube to the collector plate It. In order to avoid discharge omenabetween the conducting parts .2 and the wall *lyth'e wall is "provided,"accordingto the invention, with coatings 5 and 6 which are formed in theshape of rings and which are connected by a esnlatineawall:portion-Qsaid envelope surr und ging said electron beam over a;portion of thetravel of said beam, --a-ci-rcu-it having conductive pcritions closelyadjacent the outer side of said in- ,jsulati-ng-wall portion and havin{a slit between said conduci ive portions to efiect ,inductive .cou-:pli-ng between the saidcircuit'and the said electron beam, andeconductive Ecoatings on said in- .sulating wall portion interposedbetween said insulating wall portion-andrsaidconductive portions of saidcircuit, said coatings being in elecztricalconnectionxwithzsaidjconductivejportions.

:2. Adevice for generating 501 amplifying high frequency oscillationscomprising an electric -discharge tube having an envelope, a cathodesource of an electron beam within said envelope,

an insulatin wallportion of said envelope surrounding saideleetron beamover a portion of the travel of said beam, a cavity resonator adjacentthe outer side of the said insulating wall portiqnand having conductiveend portions and a slit closely adjacent said insulating portion toeffectjin'ductive coupling between the said resonator-iandthe saidelectron beam, and conductive coatings on said insulating wall portioninterposed between'said insulating wall portion and said conductive endportions of .said cavity resonatorpsaid coatings being in electricalconnection with said conductive end portions.

7 GERRIT .DE VRIES. EFE ENCES CI E z'Ifh-e following references are bfrecord the file of this patent:

"UNITED STATES PATENTS Number Name v Date 2,240,229 cscharli a, Apr..29, 19.41

